In recent years, a magnetic recording medium called “patterned media”, on which information can be high-densely recorded, has attracted attention. As illustrated in FIG. 15, a patterned medium is a medium whose magnetized regions (hereinafter called “land” arbitrarily) are arranged on a magnetic recording medium for record and reproduction. The magnetized regions are isolated from each other with non-magnetized regions.
The magnetic recording device, which uses such patterned media, records data by making a head magnetize the land at a timing when the head positions above the land. When reproducing the data, the magnetic recording device obtains the data by performing sampling of a reproduction signal read out from a data region at a predetermined timing. Therefore, in the magnetic recording device that uses the patterned media, it is required that the head writes the data on the land at an accurate timing and that the magnetic recording device obtains information by performing sampling of the reproduction signal at an optimum timing for the reproduction signal.
In recent years, a patterned medium that has a preamble at a head of a sector has been known. The preamble is, for example, for generating timing for data recording (hereinafter “write clock”). Such a patterned medium has a preamble for generating the timing for data reproduction (hereinafter “read clock”) at a head of a data sector.
A patterned medium which has synchronization marks for synchronizing the write clock has also been known. The synchronization marks are arranged at predetermined intervals on a track of the patterned media. Even in such a patterned medium, a preamble for generating the read clock and the like is provided at the head of the data sector.
Examples of the patterned media technology are disclosed in Japanese Laid-open Patent Publications Nos. 2000-48352, 2004-199806, and 2003-157507.